Relation of fig fruit characteristics to fruit-eating bats in the New and Old World tropics

Abstract. Long-term studies of a Panamanian fig community have revealed that the figs separate into two major groups based on distinct patterns in fruit characteristics including fruit size, colour, scent and synchrony of ripening. Furthermore, these differences can be linked to sensory, morphological and behavioural capabilities of the figs' primary dispersers. One group of figs attracts primarily bats; the other group is visited mainly by birds. Whereas fruits of 'bat' figs span a wide range of size classes, ripen synchronously and remain green(ish) when ripe, all fruits of 'bird' figs have small fruit which ripen asynchronously and turn red when ripe. Among 'bat' figs, fruit size is correlated with body size of the bats that prefer them. Based on the consistent differences between 'bat' and 'bird' fig fruits in Panama we expect similar patterns in Old World figs. Furthermore, since fig-eating bats of the Old World differ in morphology, behaviour and sensory capabilities from fig-eating bats of the New World we speculate that these differences should be reflected in differences in fruit characteristics of Old and New World 'bat' figs. Personal observations and literature reports of Old World bats and figs are consistent with our predictions.     

Differentiation during fig ontogeny suggests opposing selection by mutualists

Dioecy allows separation of female and male functions and therefore facilitates separate co‐evolutionary pathways with pollinators and seed dispersers. In monoecious figs, pollinators' offspring develop inside the syconium by consuming some of the seeds. Flower‐stage syconia must attract pollinators, then ripen and attract seed dispersers. In dioecious figs, male (“gall”) figs produce pollen but not viable seeds, as the pollinators' larvae eat all seeds, while female (“seed”) figs produce mostly viable seeds, as pollinators cannot oviposit in the ovules. Hence, gall and seed figs are under selection to attract pollinators, but only seed figs must attract seed dispersers. We test the hypothesis that seed and gall syconia at the flower stage will be similar, while at the fruiting stage they will differ. Likewise, monoecious syconia will be more similar to seed than gall figs because they must attract both pollinators and seed dispersers. We quantified syconium characteristics for 24 dioecious and 11 monoecious fig species and recorded frugivore visits. We show that seed and gall syconia are similar at the flower stage but differ at the fruit stage; monoecious syconia are more similar to seed syconia than they are to gall syconia; seed and gall syconia differentiate through their ontogeny from flower to fruit stages; and frugivores visit more monoecious and seed syconia than gall syconia. We suggest that similarity at the flower stage likely enhances pollination in both seed and gall figs and that differentiation after pollination likely enhances attractiveness to seed dispersers of syconia containing viable seeds. These ontogenetic differences between monoecious and dioecious species provide evidence of divergent responses to selection by pollinators and seed dispersers.     

Factors affecting seed rain beneath fleshy-fruited plants

We investigated factors affecting seed rain beneath nine fleshy-fruited fruiting plant species growing in a 1-ha plot of planted Pinus thunbergii in central Japan. We tested whether the numbers of seeds and seed species dropped by birds beneath fruiting plants were correlated with the number of fruits removed by birds from the plants. Most of fruiting plant species with high fruit removal had significantly high seed rain. Both the numbers of seeds and seed species dropped were significantly, positively correlated with the number of fruits removed across for all fruiting plant species. Therefore, fruit removal predicted the difference among heterospecific fruiting plants in seed rain. We also tested whether the number of fruits removed from fruiting plants by birds was related with fruit crop size, fruit size, and height of the plants, and the numbers of fruits and fruit species of neighboring plants near the plants. Most of fruiting plant species with high fruit crop size had significantly high fruit removal. The number of fruits removed was significantly, positively correlated with both the fruit crop size and the number of neighboring fruits across the nine fruiting plant species. However, the effect of the neighboring fruit density on fruit removal was lower remarkably than that of fruit crop size. Therefore, fruit crop size best predicted the differences among heterospecific fruiting plants in fruit removal. We suggest that fruiting plant species with high fruit crop size and high fruit removal contribute to intensive seed rain beneath them. This revised version was published online in June 2006 with corrections to the Cover Date.     

Fruit removal of Coprosma quadrifida (Rubiaceae) by birds in south-eastern Australia

Abstract Removal of the fleshy fruits of Coprosma quadrifida by birds was examined in relation to fruit crop size, neighbouring fruit crop size and time in the season in montane wet sclerophyll forest in south-eastern Australia. On average, 84% of individual fruit crops were removed. Frugivores removed fruit in proportion to its abundance, indicating that they continually assess availability rather than respond to a critical abundance. The size of neighbouring fruit crops did not influence fruit removal rates, suggesting that there is little competition among neighbours for dispersers. The ripe fruits of C. quadrifida were eaten by 14 bird species, comprising 50% of the bird species trapped. Silvereyes (Zosterops lateralis) were the most abundant consumers of fruits. With the exception of the parrot, Platycercus elegans, all birds defecated seeds intact and had no influence on seed viability.     

The community structure of bird assemblages on urban strangler figs

Figs have been regarded as keystone plant resources that support diverse tropical vertebrate frugivore communities. Planting or conserving large fig trees, such as stranglers, have therefore been proposed for enhancing urban biodiversity. We compared the diversity and community structure of bird assemblages on strangler figs with non‐fig urban trees as well as between the fruiting and non‐fruiting fig trees in an urban setting in Singapore. The total bird abundance across all the fig trees when in fruit was 4.5‐fold higher than on non‐fig trees and 3.5‐fold higher than when the same fig trees were not fruiting, but only attracted two more species. On individual trees, after accounting for the presence of mistletoes, tree height, the area covered by buildings, road lane density, and the distance to natural vegetation, mean diversity was not different between non‐fig trees and fig trees when they were not in fruit. On the other hand, when fruiting, each fig tree on average had 1.4 more species, 3 more counts of non‐native birds, and 1.6 more counts of insectivorous birds than when not fruiting. There was significant compositional turnover between non‐fig trees and non‐fruiting fig trees, while community dispersion was significantly lower among fig trees in fruit. Our results demonstrate that fig trees provide fruit and non‐fruit resources for birds in an urban landscape but do not necessarily support more diverse total bird assemblages than non‐fig trees. Instead, bird communities on fruiting urban figs would be highly homogeneous and dominated by a few species. Abstract in Malay is available with online material.     

Facultative ripening in Hamelia patens (Rubiaceae): effects of fruit removal and rotting

Summary In Costa Rica individual Hamelia patens trees produce fruit throughout the year and experience dramatic changes in rates of fruit removal and rotting. During some moths, most fruits rot because they are not removed. Rotting fruits increase the probability that other fruits on the same infructescence will rot. When removal rates are high, fruits are taken as soon as their seeds become viable but before the fruit is completely ripe. Experimental removal of fruits produced significantly higher ripening rates than on control infructescences. This response allows Hamelia to ripen more fruit and increase the number of fruits taken when dispersers are abundant (e.g., during migration). The proximate mechanism of this response probably includes reallocation of energy conserved when partially ripe fruits are removed. Responding to fluctuating disperser populations likely increases dispersal success and may function as the ultimate cause.     

The figs of winter: Seasonal importance of fruiting fig trees (Ficus: Moraceae) for urban birds

Birds and figs are conspicuous members of the tropical and subtropical ecosystems. Because they are easily observed and very speciose, their relationships have been well studied in many areas, and the figs are considered a keystone resource for many bird species which are efficient fig seed dispersers. Taiwan has a relatively high endemism rate for many taxa (17% of bird species) but because of its high human population density, most lowland habitats are heavily developed, of which much of it covered by dense urban habitation. To establish the importance of urban figs for birds, we focused our surveys mostly on three common urban fig species (Ficus caulocarpa, F. microcarpa and F. subpisocarpa). We observed trees with ripening figs from July 2013 to December 2016 in order to determine the composition of the fig-consuming bird community. In addition, we added all the information available in the scientific literature and birdwatchers' observations which we could find. In total, we observed 42 bird species consuming 18 fig species. The bird diversity in urban areas was non-negligible even during winter. Therefore, there are two reasons why figs are important for Taiwan's bird avifauna: in cities, the tree diversity is generally low so that figs provide a stable food resource; and since figs are fruiting all year-round, they are one of the few reliable resources available during winter when many migrant birds overwinter in Taiwan. Already crucial for many species in tropical and subtropical forests, fig trees may also be essential for urban birds in tropical and subtropical regions.     

Influence of between-year variation in the density of Rhus <Emphasis Type="Italic">trichocarpa</Emphasis> fruits on the removal of fruit by birds

The fruiting phenology and fruit removal patterns of Rhus trichocarpa Miq. (Anacardiaceae) were investigated in a warm-temperate secondary forest in Japan. Mature fruits of this species are dispersed by birds. Effects of fruit display size and canopy openness on fruit removal were investigated in years with different fruit densities (i.e., masting and non-masting years). Moreover, effects of increased canopy openness during winter on fruit removal were also investigated. Seasonal patterns of fruit removal were quite different between masting and non- masting years. In the non-mast year, fruits were removed by birds soon after maturation in the summer. In contrast, in the mast year, fruits were removed gradually by birds from summer to winter. Moreover, the rate of fruit removal was greater for trees with a larger display size in the non-mast year, whereas that was greater for trees with greater canopy openness in the mast year. Canopy openness increased in winter, and fruit removal in winter was enhanced in trees with a more open canopy only in the non-mast year. These observations strongly suggest that avian dispersers became satiated in the mast year, whereas fruit removal was enhanced in the non-mast year. In the mast year, although many fruits were not dispersed until winter, they were neither depredated nor rotten, and the long period of fruit removal by birds may have enhanced fruit dispersal. The large abundance of seedlings and saplings of this species in Japanese secondary forests suggests that this fruiting strategy is beneficial.     

A field test of the directed deterrence hypothesis in two species of wild chili

The directed deterrence hypothesis posits that secondary metabolites in ripe fruit function to deter fruit consumption by vertebrates that do not disperse seeds, while not impacting consumption by those that do. We tested this hypothesis in two species of wild chilies (Capsicum spp.). Both produce fruits that contain capsaicinoids, the compounds responsible for the pungency of chilies. Previous work suggests seed-dispersing birds but not seed-destroying rodents consume chili fruits, presumably because rodents are deterred by capsaicin. However, fruit removal from chili plants by rodents and other mammals has not been previously explored. Because laboratory rodents can develop a preference for capsaicin, it is quite possible that wild rodents are natural consumers of chili fruits. We monitored the fate of 125 marked fruits of Capsicum chacoense and 291 fruits of Capsicum annuum. For both species, essentially all fruit removal occurred during the day, when rodents are inactive. Video monitoring revealed fruit removal only by birds, mostly by species known to disperse chili seeds in viable condition. Furthermore, these species are from taxonomic groups that tend to specialize on lipid-rich fruits. Both species of chili produce fruits that are unusually high in lipids (35% in C. chacoense, 24% in C. annuum). These results support the directed deterrence hypothesis and suggest that fruiting plants distinguish between seed predators and seed dispersers by producing fruits that repel the former and attract the latter.     

Frugivory on Persea lingue in temperate Chilean forests: interactions between fruit availability and habitat fragmentation across multiple spatial scales

Habitat degradation and fragmentation are expected to reduce seed dispersal rates by reducing fruit availability as well as the movement and abundance of frugivores. These deleterious impacts may also interact with each other at different spatial scales, leading to nonlinear effects of fruit abundance on seed dispersal. In this study we assessed whether the degradation and fragmentation of southern Chilean forests had the potential to restrict seed dispersal the lingue (Persea lingue) tree, a fleshy-fruited tree species. Of five frugivore bird species, the austral thrush (Turdus falcklandii) and the fire-eyed diucon (Xolmis pyrope) were the only legitimate seed dispersers as well as being the most abundant species visiting lingue trees. The results showed little or no direct effect of habitat fragmentation on seed dispersal estimates, possibly because the assemblage of frugivore birds was comprised habitat-generalist species. Instead, the number of fruits removed per focal tree exhibited an enhanced response to crop size, but only in the more connected fragments. In the fruit-richer fragment networks, there was an increased fragment-size effect on the proportion of fruits removed in comparison to fruit-poor networks in which the fragment size effect was spurious. We suggest that such nonlinear effects are widespread in fragmented forest regions, resulting from the link between the spatial scales over which frugivores sample resources and the spatial heterogeneity in fruiting resources caused by habitat fragmentation and degradation.     

Nutritional Values of 14 Fig Species and Bat Feeding Preferences in Panama1

Figs are a critical resource for many tropical frugivores, yet they often are referred to as low quality fruits. To determine their nutritional value, both as a group and for individual species, we analyzed 14 fig species from Barro Colorado Island (BCI), Panama, for fiber, tannins, lipids, protein, carbohydrates, amino acids, and minerals. Seeds and pulp were analyzed separately. Fig fruit pulp consisted of about one‐third digestible components, mostly carbohydrates with some lipids and proteins. Tannin, lignin, and water‐soluble carbohydrates showed considerable variation among species, as did fruit size. Figs contained high amounts of amino acids, such as leucine, lysine, valine, and arginine, and minerals, such as potassium, calcium, magnesium, sodium, and phosphorus. One species, Ficus insipida, contained the highest concentrations of almost all amino acids, many minerals, and protein. Small figs had as much nutritional value per gram as large figs. Free‐standing figs had higher percentages of protein, complex carbohydrates, and ash than strangler figs, which had higher percentages of water‐soluble carbohydrates, tannins, and hemicellulose. The guild of fruit‐eating bats on BCI included ten common species with diets dominated by figs. Fecal analyses and captures at ripe fig trees showed a consistent pattern of resource partitioning. Small bats preferentially ate small‐fruited and strangler figs while large bats consumed mostly large‐fruited and free‐standing figs. Small bats most often ate F. bullenei, which has high levels of lipid and carbohydrates, and F. yoponensis, which has high levels of protein. Medium and large bats most often ate F. insipida, a nutritionally superior species; their second most eaten species was F. obtusifolia, in which the large size may make it efficient to eat. Each bat ate a variety of fig species, supporting the idea that although no single species of fig may be sufficient to sustain frugivores, a mix of fig species can provide a complete set of nutrients.     

Crop Size and Fruit Neighborhood Effects on Bird Visitation to Fruiting Schefflera morototoni Trees in Puerto Rico1

Studies of zoochorous seed dispersal systems often consider crop size, yet seldom consider the kinds and amounts of fruits surrounding parent plants (the fruit neighborhood) when attempting to explain among‐plant variation in fruit removal. We studied avian frugivory at 24 Schefflera morototoni trees from February to May 1998 in central Puerto Rico. The number of fruits removed by avian seed dispersers per visit was similar among focal trees (typically 2–4). In contrast, visitation rate was highly variable (range: 0–71 visits per 4 h). We used multiple regression analyses to evaluate the relative roles of crop size (focal tree ripe fruit abundance) and fruit neighborhood variables (measured within 30 m of focal trees) in affecting visitation to focal trees by avian frugivores. Visitation rate was positively related to crop size (although this variable was only significant in one of four regression models considered) and negatively related to the presence or abundance of conspecific fruits, suggesting that trees competed intraspecifically for dispersers. Relationships between visitation and heterospecific fruits were mixed—some kinds of fruits appeared to enhance visitation to focal trees, while others seemed to reduce visitation. In most regression models, neighborhood variables had larger effects on visitation than focal tree fruit crop size. Our results highlight the important effects of local fruiting environments on the ability of individual plants to attract seed dispersers.     

Crop size,plant aggregation,and microhabitat type affect fruit removal by birds from individual melastome plants in the Upper Amazon

We studied the efficiency (proportion of the crop removed) and quantitative effectiveness (number of fruits removed) of dispersal of Miconia fosteri and M. serrulata (Melastomataceae) seeds by birds in lowland tropical wet forest of Ecuador. Specifically, we examined variation in fruit removal in order to reveal the spatial scale at which crop size influences seed dispersal outcome of individual plants, and to evaluate how the effect of crop size on plant dispersal success may be affected by conspecific fruit abundance and by the spatial distribution of frugivore abundance. We established two 9-ha plots in undisturbed terra-firme understory, where six manakin species (Pipridae) disperse most seeds of these two plant species. Mean levels of fruit removal were low for both species, with high variability among plants. In general, plants with larger crop sizes experienced greater efficiency and effectiveness of fruit removal than plants with smaller crops. Fruit removal, however, was also influenced by microhabitat, such as local topography and local neighborhood. Fruit-rich and disperser-rich patches overlapped spatially for M. fosteri but not M. serrulata, nonetheless fruit removal of M. serrulata was still much greater in fruit-rich patches. Fruit removal from individual plants did not decrease in patches with many fruiting conspecifics and, in fact, removal effectiveness was enhanced for M. fosteri with small crop sizes when such plants were in patches with more conspecifics. These results suggest that benefits of attracting dispersers to a patch balanced or outweighed the costs of competition for dispersers. Spatial pattern of fruit removal, a measure of plant fitness, depended on a complex interaction among plant traits, spatial patterns of plant distribution, and disperser behavior.     

Patterns of frugivory in the columnar cactus Pilosocereus leucocephalus

In the frugivory networks of many arid and semi‐arid Mesoamerican ecosystems, columnar cacti act as keystone species that produce fruits with a high content of water and nutrients attractive to numerous vertebrates. The aim of this investigation was to assess the fruit removal patterns of two guilds of frugivores on the fruits of the woolly torch Pilosocereus leucocephalus. We assessed fruit pulp removal in two ways: by estimating the consumption of seeds given the amount of pulp removed per visit and by estimating the percentage of pulp removal over time. We put exclosures on unripe, intact fruits to keep frugivores from removing material. Once ripe, we removed the exclosures and tracked animal visitation of 69 fruits using camera traps. We obtained a total of 2,162 hr of footage (14:47 hours of them with effective pulp removal). The highest number of visitors is that of diurnal species (n = 12, all birds) versus only four nocturnal (three bats, one rodent). The most effective species in pulp removal are birds. Bats play a modest role in frugivory of this cactus. The significance of this work is twofold: (a) birds and bats consume the fruit pulp of this cactus and likely disperse its seeds, and (b) although bats rank high in pulp removal effectiveness, birds as a guild far outweigh their importance in this system, as they are not only more frequent but also remove more pulp and seeds. Both groups are known to be important in cacti seed dispersal, and our findings are essential in understanding the population dynamics of the woolly torch and in elucidating its seed dispersal ecology.     

PHENOLOGY,SEED DISPERSAL,AND COLONIZATION IN MUNTINGIA CALABURA,A NEOTROPICAL PIONEER TREE

In this paper we describe the phenology, fruiting ecology, and colonization ability of a widespread neotropical pioneer tree, Muntingia calabura (Eleocarpaceae), in Costa Rican dry tropical forest. Individuals of M. calabura grow rapidly, flower at <2 yr age, and produce juicy red fruits containing thousands of tiny seeds that are eaten by a variety of frugivorous birds, bats, and monkeys. Although most individuals produce some flowers and fruit year-round, peak flowering occurs in the late dry season (April–May), and peak fruit availability occurs early in the wet season (May–June). Bats and parakeets are the major seed dispersers of M. calabura at our study site, and they concentrate their attention on this species at its fruit peak when few alternate fruits are available. Germinable M. calabura seeds accumulate in the forest soil in relatively high density in areas of high frugivore activity. M. calabura can quickly invade large disturbed areas with a high density of seedlings. Adult densities decline from thousands of individuals/ha to a few individuals/ha in a relatively few years. Clumps of M. calabura trees are replaced by later successional species in < 30 yr.     

Seed Dispersal in the Dark: Shedding Light on the Role of Fruit Bats in Africa

In spite of their recognized importance as seed dispersers in other parts of the tropics, seed dispersal by fruit bats has received scant research attention in Africa. To evaluate the role of African fruit bats in seed dispersal, we studied fruits and seeds below 480 bat feeding roosts in the East Usambara Mountains of Tanzania. We compared these findings to those reported in other African localities to place our results in a broader context. We found 49 plant species dispersed by bats: 28 species, 18 genera, and one family are novel reports of bat dispersal in Africa. Approximately 20 percent of the submontane tree flora of the East Usambaras is bat‐dispersed, including both widespread and endemic trees. African fruit bats are important seed dispersers at our study site because they move seeds of dozens of species tens or hundreds of meters, even seeds that are too large to ingest (greater than 5 mm in length). Fruit bats are likely important seed dispersers in other Afrotropical forests, as bats elsewhere in Africa are known to consume 20 genera and 16 species of plants reported here. Insights from studying remains under bat feeding roosts offer a simple method to further document and substantially increase our understanding of the role of African fruit bats in seed dispersal.     

Crop size is more important than neighborhood fruit availability for fruit removal of <Emphasis Type="Italic">Eugenia uniflora</Emphasis> (Myrtaceae) by bird seed dispersers

For a plant with bird-dispersed seeds, the effectiveness of seed dispersal can change with fruit availability at scales ranging from individual plants to neighborhoods, and the scale at which frugivory patterns emerge may be specific for frugivorous species differing in their life-history and behavior. The authors explore the influence of multispecies fruit availability at two local spatial scales on fruit consumption of Eugenia uniflora trees for two functional groups of birds. The authors related visitation and fruit removal by fruit gulpers and pulp mashers to crop size and conspecific and heterospecific fruit abundance to assess the potential roles that facilitative or competitive interactions play on seed dispersal. The same fruiting scenario influenced fruit gulpers (legitimate seed dispersers) and pulp mashers (inefficient dispersers) in different ways. Visits and fruit removal by legitimate seed dispersers were positively related to crop size and slightly related to conspecific, but not to heterospecific fruit neighborhoods. Visits and fruit consumption by pulp mashers was not related to crop size and decreased with heterospecific fruit availability in neighborhoods; however, this might not result in competition for dispersers. The weak evidence for facilitative or competitive processes suggest that interaction of E. uniflora with seed dispersers may depend primarily on crop size or other plant’s attributes susceptible to selection. The results give limited support to the hypothesis that spatial patterns of fruit availability influence fruit consumption by birds, and highlight the importance of considering separately legitimate and inefficient dispersers to explain the mechanisms that lie behind spatial patterns of seed dispersal.     

Chemical tradeoffs in seed dispersal: defensive metabolites in fruits deter consumption by mutualist bats

Although fleshy fruits function primarily to attract seed dispersers, many animal‐dispersed fruits contain potentially toxic secondary metabolites. These metabolites can provide defense against seed predators and pathogens, but their effects on dispersers are still poorly understood. In some cases plants may experience a tradeoff, where the metabolites that provide fruit defense also reduce seed disperser preferences. In other cases the bioactivity of fruit secondary metabolites may be directed primarily at pests with no negative effects on seed‐dispersing vertebrates. We tested the effects of amides, a group of nitrogen‐based defensive compounds common in the plant genus Piper (Piperaceae), in interactions with the primary seed dispersers of Piper in the neotropics – fruit‐feeding bats in the genus Carollia (Phyllostomidae). In a series of flight cage experiments, pure amides and amide‐rich fruit extracts reduced the preferences of bats for Piper fruit, affecting both the bats’ initial choices to remove Piper infructescences and the proportion of fruit consumed from individual infructescences once they were removed. However, the effects of amides varied considerably among three species of Carollia and among the specific individual amides and extracts tested. Overall, our results support the hypothesis that plants experience a tradeoff between seed dispersal and fruit defense, but the strength of this tradeoff and the overall fitness consequences may depend strongly on ecological context.     

Why do fleshy-fruit plants of the mediterranean scrub intercept fall-but not spring-passage of seed-dispersing migratory birds?

Summary Production of fleshy fruits by 8 tree and shrub species, and patterns of their utilization by 6 resident and 6 transient bird species, were assessed in an Israeli Mediterranean scrub. Whereas more than half the ripe crop of plants that fruit in one relatively short burst is not removed by birds, the greater part of the crop of species that fruit throughout a long period, is removed. Of two plant species that fruit simultaneously, the one with an inconspicuous fruit is utilized by a single, year-round resident frugivorous bird, whereas the species with bright fruits is utilized by several non-resident and omnivorous bird species. A further two simultaneously fruiting species differ in fat content and the color of their conspicuous ripe fruits; the low-fat fruit being taken by a resident species and the high-fat fruit by a transient congener, just prior to the desert-crossing portion of its Fall-passage.Though more migrants pass through in Spring than in Fall, none of the fleshy-fruit plants fruit in Spring, and most fruit during the Fall. Two non-exclusive explanations for this phenomenon are (a) Fall dispersal ensures immediate germination, with least exposure to desiccation and predation; (b) Spring transients approaching their breeding territories may either be reluctant to spend much time on feeding, or mostly require proteins, amply supplied by the Spring flush of insects, typical of the Mediterranean region. Fall transients approaching the desert require mostly fats and carbohydrates, supplied by fruits. Fruits attract birds easily in the Fall, when insects are scarce.     

The role of fruit diet within a temperate breeding bird community in southern Spain

In southern temperate regions many fleshy-fruited plant species ripen their fruits during the breeding or early post-breeding season and these are consumed by resident birds. I studied the frugivore community of the summer-fruiting tree Frangula alnus ssp. baetica in southern Spain and the significance of fruit in the diet of adult and recently fledged birds. Twelve species consumed F. alnus fruits. Almost 97% of the foraging visits were carried out by the four most abundant species, Robin Erithacus rubecula, Blackcap Sylvia atricapilla, Blackbird Turdus merula and Blue Tit Parus caeruleus. During the ripening season Robins and Blackcaps concentrated at fruit-rich sites. Entire families of Blackcap and Blackbird regularly entered fruiting trees together. In contrast, adult Robins always foraged solitarily, and accounted for only 4% of the tree visits, while 96% were realized by recently fledged birds of the first brood. In all species, young birds foraged as efficiently as adults. F. alnus fruits are not part of the regular nestling diet, but they are a significant part of the diet for recently fledged Robins during their postnatal dispersal. Conversely, these are the most important and effective seed dispersers while adult Robins scarcely take part in the dispersal of F. alnus seeds.